It's a funny meme, but I think Destiny would argue that what he's upset about isn't Brittany airing her feelings out on stream, it's that she would have those feelings in the first place. No amount of boundaries that he could have imposed (without violating her autonomy) would have changed this situation. At best, such a boundary would have prevented her from going public about her feelings.

However, what I think Destiny is overlooking (it was only tangentially brought up on stream yesterday) is that a huge part of Brittany (and others like Hasan, Vaush, and the crazies like Sunday, Mr and Ms [Redacted]) spiraling out of control is her personal ego/hubris with respect to the eyes of the public audience. Essentially, she is unwilling to lose face, so instead of walking things back when shown to be wrong, she continually doubles down until it gets to the point that the only way to make it all go away is to eliminate the source of the contradiction/criticism (i.e. find ways of invalidating/destroying Destiny). Where boundaries can come into play here is that potentially, if Brittany (or any of the other individuals) had been prevented or delayed from giving a public opinion, she might not have forced herself to commit so dogmatically to her original take and could have been reasoned out of her spiraling.